1. Field of the Invention
This invention relates to a barrel adjustment and retaining assembly, more particularly to a barrel adjustment and retaining assembly applicable to a variable-focus flashlight.
2. Description of the Related Art
Barrel adjustment and retaining assemblies have been widely developed in various applications in daily life, for example, a focus-adjustable flashlight that allows the user to adjust the relative position of an optical lens and an internal light source so as to provide a variable-focus effect from a wide floodlight to a narrow beam, or a finderscope that includes an eyepiece (or called an ocular lens) and an objective lens. The eyepiece is movable relative to the objective lens for conforming with different users.
Referring to FIGS. 1 and 2, a conventional barrel adjustment and retaining assembly includes a barrel body 11, an adjustment barrel 12 that has a large inner diameter (d1) and a small inner diameter (d2), that is sleeved on the barrel body 11, and that is movable on the barrel body 11 along an axial direction of the barrel body 11, a seat body 13 including a protrusion 131 and threaded to the barrel body 11, a light emitting element 14 disposed in the seat body 13, an optical lens 15 disposed in the adjustment barrel 12 and aligned with the light emitting element 14 along the axial direction, and a cover 16 threaded to the adjustment barrel 12 so as to secure the optical lens 15 to the adjustment barrel 12.
Since the protrusion 131 is made of a rigid material, and must have a diameter that is smaller than d1 and larger than d2. That is, during manufacture, a demand of a high-precision is required for the protrusion 131.
Moreover, since the seat body 13 is made of metal, the adjustment barrel 12 is likely to be damaged during relative movements between the protrusion 131 of the seat body 13 and the adjustment barrel 12, vibration and collision occur therebetween. Furthermore, during assembly, the barrel adjustment and retaining assembly is assembled in the following steps of: (a) sleeving the barrel body 11 in the adjustment barrel 12; (b) threading the seat body 13 on the barrel body 11; (c) connecting the optical lens 15 to the adjustment barrel 12; and (d) threading the cover 16 on the adjustment barrel 16. It should be noted that the steps must be done in a specific sequence, and therefore the assembling process is relatively difficult and time consuming. Moreover, the number of the components is relatively large and therefore the manufacturing cost is relatively high.